Auxiliary Heat vs. Emergency Heat

Ever notice one of these options show up on your thermostat? Here’s more on Auxiliary Heat vs. Emergency Heat:

To start, why might one of these show up? Heat pumps are the part of your HVAC system that is meant to heat your home or commercial building. However, sometimes the weather gets too cold and the heat pump struggles to keep up. Heat pumps are only meant to heat up to 20F warmer than the outside temperature. Thus, when it is 32F but the thermostat is set for 68F, the system struggles. This is when Auxiliary Heat and Emergency Heat come into play:


Auxiliary Heat is turned on and off automatically by the heat pump when the system is unable to produce enough heat on it’s own. The heat from the auxiliary is produced from electric heating coils and electric resistance heating. The heat pump turns the auxiliary heat on and off depending on if the heat pump needs help due to the colder weather or when the heat pump goes into defrost. Auxiliary is used as a secondary heating source.

Note: When the Heat Pump goes into defrost, there may be water coming from the outside system. Do not worry, the outside coil is defrosting to allow the system to heat your home or commercial building.

Emergency Heat:

Emergency Heat is a remote heating cycle for when the temperature is below freezing. The heat it provides is from radiation heat strips and must be turned on and off manually. Furthermore, emergency heat should only be turned on when it is 30F or lower outside. Also, the heat pump and compressor must be turned off. Emergency heat is used to prevent damage to the heat pump system, while providing heat to your home.

To learn more about protecting your system, click here.

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North Myrtle Beach HVAC & Refrigeration

LHT Cooling, Heating & Refrigeration is a North Myrtle Beach HVAC and commercial refrigeration company serving the South Carolina Grand Strand, Carolina Shores and North Carolina. LHT services and repairs heat pumps, heating units, air conditioning units, furnaces, ventilation systems, indoor air quality, humidifications, ductless systems, boilers, reach-in coolers, walk-in coolers, reach-in freezers, walk-in freezers, ice machines, blast chillers and refrigerated displays.

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